Young workers are vulnerable to occupational hazards and are at a greater risk of being injured at work. Inexperience, lack of safety training and inadequate skills for dealing with work-related hazards undermine the occupational safety of young people. In addition, young individuals often work in low-skilled and manual jobs that involve a higher risk of accidents. Prior research has shown that the majority of accidents at work are caused by factors related to human behavior. By enhancing safety preparedness, increasing safety motivation and modifying the safety locus of control and safety attitudes, it is possible to influence young individual's abilities of protecting themselves from occupational hazards. The main purpose of this study was to extend our understanding of effective methods that help young people play active role in occupational safety. The efficacy and implementation process of a student-centered safety training program was investigated in a school-based randomized controlled trial carried out in eight Finnish vocational schools. The safety training program was based on social-cognitive theories and utilized a peer learning process. The study comprised three sub-studies. The results of Sub-study I indicate that the safety training program enhanced safety preparedness, increased internal safety locus of control and reduced risk attitudes among students. Sub-study II detected a significant increase in safety motivation. Furthermore, the effect of safety training on internal safety locus of control was associated with motivational outcomes. These results provide practical implications for designing school-based safety training and increase our understanding of the antecedents of safety motivation. The efficacy evaluation was complemented by analysis of the implementation process in Sub-study III. The results showed that adherence to the intervention program and quality of delivery were associated with student outcomes. The target group perspective of the intervention fidelity assessment provided new insights into the evaluation of the implementation process of school-based preventive interventions. Furthermore, the identification of the key active ingredients of the safety training program helped determine specific practices that facilitate the desired change among students. Overall, this study suggests that a student-centered safety training approach has a positive impact on the antecedents of safety behaviors. The results provide practical suggestions for school-based safety training and help equip young people with readiness to promote occupational safety and resilience to overcome barriers to safe work.